本文主要研究於不同孔隙比之筐網圓柱定床試驗中，實際量測筐網圓柱周圍流場之水深、流速等資料，並對此加以分析，以瞭解筐網圓柱流場之平均流速、流場紊流強度、水流隨時間之變動與速度頻譜等與不同筐網圓柱孔隙比之關係。
由實驗結果與相關理論驗證得知，水流通過不透水圓柱時，結構物後方流場極度紊亂，然而當水流通過筐網圓柱後，將於結構物後方產生一流況穩定且流速低之「穩定低速區」。將實驗結果與石武融(2007)成果比較顯示，當孔隙比增加，最大流速衰退率(Udm)將減小，而發生之位置會向下游延伸，此結果可提供筐網圓柱現地擺設之數據參考。

To clarify the effect of different porosity to a porous cylinder, a series of experiments were executed. The Profiling Velocimeter was used to measure the flow field around and behind the porous cylinder, including the depth-averaged velocity distribution, time sequence analysis of velocity and disturbance level to examine the characteristics of the effect due to different porous cylinder.
Comparison of the experiment results and the related researches, the velocity and turbulence intensity after the impermeable cylinder was intensely changed. However, the flow field after the porous cylinder was steady and a steady low-velocity region was formed. In present experiment reports, as the porosity increased, the maximum velocity decay value decreased and the position where the minimum velocity occurred would move towards to downstream direction. While the porous cylinder was applied in the field, these results could provide as a design reference .

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